Boots are a type of footwear that encase both the foot and a portion of the lower leg of a user. Boots are generally manufactured for a particular purpose or activity and are therefore designed to include characteristics consistent with the intended purpose. For example, a hiking boot is designed to support the ankle of a user while minimizing the overall weight. Likewise, a ski boot is designed to maximize a user's performance at a particular skiing activity.
Boots generally include a shell, a compression system, and a sole. The shell and compression system operate to encase and support the foot and lower leg of a user. Various well-known shell and compression systems are utilized to allow users to insert and remove their foot in an open boot configuration and compress the shell around the foot in a closed boot configuration. The sole of a boot is disposed on the bottom surface of the shell. The sole is generally composed of a rubber or plastic material. The sole may be composed of a single piece or multiple blocks.
The general activity of skiing includes many subset activities, including but not limited to alpine touring, telemark, and downhill. Each subset of skiing generally corresponds to a unique system of specialized equipment. For example, the boot, ski, and binding systems used for telemark skiing are significantly different from those used for alpine touring. A skiing system may include standard types of boots, skis, and bindings. Each type of skiing also corresponds to unique boot characteristics for optimal performance. In addition, particular terrain and skier preference may require an even more specific set of performance characteristics. Boots for particular skiing activities must be compatible with the remainder of the system. For example, telemark skiing boots have generally been required to conform to the 75 mm standard to allow for compatibility with telemark-type bindings. In addition, telemark boots include an articulation region proximal to the dorsal metatarsal region of the foot. This articulation region allows skiers to pivot or articulate a rear portion of their boot about a front portion fixed to a ski. However, to maximize telemark performance in the remainder of the boot, it must be composed of a substantially rigid and lightweight material. Therefore, modern telemark boots generally include a bellows region and are composed of plastic composite materials. The bellows region is an opening in the rigid material that allows for articulation. The bellows region is often covered to prevent debris and snow from entering the internal region of the boot.
One of the problems with existing bellow regions relates to torsional stability. By including an opening in a rigid boot shell across the dorsal metatarsal region of a boot, the boot is intentionally allowed to vertically pivot in the sagittal plane about that point. However, this opening also enables undesirable side to side movements in the frontal plane about the same point. The side to side movements may also be referred to as torsional movement because the movements often include a degree of rotation about the fixed frontal region of the boot while attached to the ski. A telemark boot's performance is diminished by allowing these torsional movements.
Therefore, there is a need in the industry for a boot bellows region that enables vertical pivoting in the sagittal plane while providing support in the frontal plane so as to minimize side to side movements in the frontal plane.